The body speaks volumes about what ails it -- from obvious warnings like a fever that accompanies an infection to subtle clues like losing hair on the toes, which can be an early sign of vascular disease.
Some signs that seem alarming may actually be harmless: Bright-red stools are more likely to come from eating beets than from intestinal bleeding. But some that seem minor can warn of a serious disorder. Small yellow bumps on the eyelid, for instance, may be fatty deposits that signal high cholesterol, which in turn raises the risk of heart disease.
Other signs seem to make no logical biological sense: Eyebrows that no longer extend over the corners of the eyes can indicate an underactive thyroid, and a diagonal crease in the earlobe seems to herald a heightened risk of heart attack.
Some body signs can have a confusing range of meanings: Does that bulging tummy signify middle-aged spread or the beginning of ovarian cancer?
The problem is that many of us don't recognize the warnings, even when they're staring us in the face. Medical writer Joan Liebmann-Smith was losing weight rapidly. Her hair was falling out. Her heart was racing, and she couldn't sleep. She chalked up her symptoms to the stress of having a new baby, while a psychiatrist she consulted for insomnia told her to just 'count sheep.'
Over lunch one day, a relative looked at her bulging eyes and the big lump in her throat and said, 'Joan -- you have a goiter!' A blood test confirmed that she had an advanced case of Grave's disease, an autoimmune disorder that causes the thyroid gland to swell and produce too much of the powerful hormone.
'I had all the classic signs, and I ignored them,' says Ms. Liebmann-Smith, a medical writer, who resolved to write a guide for laymen to the warning signs of serious illnesses. 'Body Signs' -- written with Jacqueline Nardi Egan, a breast-cancer survivor -- came out in 2007 and has since been published in 26 countries.
'We don't want people to panic and jump to conclusions,' Ms. Liebmann-Smith says. 'But it's important to pay attention to your body. Knowledge is power.'
Before you race off to the doctor for every lump or discoloration, remember that anomalies you've had for years are more likely to be a harmless part of your genetic makeup. Signs and symptoms that are unusual for you, or painful or debilitating, are more likely to be significant. (Signs are external indicators that can be seen or felt; symptoms are internal sensations, such as pain, that only the patient can perceive.)
Examining a patient from head to toe for such indicators is a key part of every nurse's training. 'It's the foundation of patient care,' says Susan Denman, a family nurse practitioner who teaches physical assessment at the Duke University School of Nursing. Knowing how to interpret all those signs and symptoms takes up much of a doctor's education and is refined over a lifetime of clinical practice.
But many doctors and nurses alike say that patients, too, should be vigilant for anything new or unusual about their own bodies. 'The more engaged patients can be, the better,' says Ted Epperly, president of the American Academy of Family Physicians, who maintains a practice in Boise, Idaho.
With major changes to the nation's health-care system looming, it may be more important than ever for people to keep track of their own physical health. Primary-care doctors could become increasingly pressed for time, and long-term doctor-patient relationships may be harder to sustain. The growing emphasis on preventive medicine may also place more responsibility on patients to head off illnesses before they become serious.
Diabetes alone costs the nation an estimated $174 billion annually; people with diabetes have more than twice the average medical bills than those without. Signs of diabetes show up all over the body, from bleeding gums to tingling feet to darkened skin patches on the neck and underarms.
Some of the most worrisome body signs are already well known, thanks to extensive education campaigns. Most women know to check their breasts regularly for lumps, dimples, swelling and discharge that can signify cancer, and to have regular mammograms. 'Not all breast lumps are bad, but they all need to get checked out,' says Jen Brull, a family physician in Plainville, Kan.
Men can develop breast cancer too, with many of the same symptoms. Enlarged breasts in men, known as gynecomastia, generally indicates an imbalance of estrogen and testosterone, which can occur from puberty or aging -- or it could be a sign of kidney disease, or a pituitary tumor.
Skin cancers have also gotten significant publicity. When evaluating a spot, remember 'ABCDE,' says Margaret Parsons, a dermatologist in Sacramento, Calif.: It may be malignant if it has A, for an asymmetrical shape; B for a jagged or irregular border; C for a suspicious color; D for a diameter larger than a pencil eraser; and E for being elevated and uneven. Basal-cell carcinomas and squamous-cell carcinomas tend to be red to pink and crusty, and bleed easily. 'If you see anything like that, you should be checked,' Dr. Parsons says.
Excess belly fat is becoming notorious as a sign of a heightened risk of diabetes, high blood pressure, stroke, heart disease, gall-bladder disease and numerous cancers. Waist-to-hip ratios are especially telling: If a man's waist is larger than his hips, or a women's waist is more than four-fifths her hip circumference, that's a sign that dangerous visceral fat is surrounding an abdominal organ.
A high body-mass index is a red flag in general to clinicians. But sudden, unexplained weight loss can be even more worrisome. 'In this day and age, people tend to gain weight. If somebody loses weight without trying, that could be a sign of depression or a gastrointestinal illness or a malabsorption syndrome. Even diabetes can cause you to lose weight,' says Dr. Brull.
Many other signs of possible illness are less well-publicized. Thyroid disease can manifest itself in dry, brittle hair, brittle nails, and weight gain or loss. Losing hair on the rest of your body could be aging or menopause, or a metabolic disorder or circulatory problems.
'If I see a patient with a horizontal line through the middle of the fingernails, I'll ask what happened three months ago -- were they horribly ill or did someone die? They think I'm brilliant,' says Dr. Parsons. The markings, called Beau's Lines, sometimes appear when the body is particularly stressed. 'Your body is busy, so your nails take a little break and then start growing again,' Dr. Parsons says.
Nails tell other tales as well. White nail beds -- the skin underneath the nail -- can signify anemia. Nails that are white near the cuticle and red or brown near the tip can be a sign of kidney disease. Irregularly shaped brown or blue spots in the nail bed can be melanomas. Fingertips that are blue or clubbed can be a sign of lung disease -- although generally, there would be more significant signs as well.
Many of the same signs occur in toenails. But the feet are critical for other reasons. 'Feet tell you a huge amount about the health of the circulation,' says Dr. Denman, the Duke nursing instructor. 'The first place that vascular disease can show up is where the blood vessels are the smallest and the farthest away from the heart.'
Circulatory problems can manifest themselves as numbness and tingling in the feet; so can peripheral neuropathy, or damage to the nerves that often begins at the extremities. Both are signs of uncontrolled diabetes. With circulation compromised, even a minor scratch or sore on the feet can become infected easily; lack of sensation can make it easy to ignore, and gangrene can set in, requiring amputation. That's why people with diabetes are urged to check their feet every day for any kind of scratch or lesion.
The mouth provides another window into overall health. That's what inspired New York University's College of Dentistry to team up with its College of Nursing to check patients at the university's free dental clinic for other health-related issues. More than 60% of the patients referred from the dental clinic met the criteria for hypertension, and 30% had diabetes or pre-diabetes. 'The tooth pain brings them in. Diabetes and hypertension are often silent diseases,' says Edwidge Thomas, the nursing school's director of clinical practice affairs.
In rarer cases, gums can bleed and become inflamed from leukemia. Bulimia can leave telltale acid marks on the backs of teeth -- and missing teeth can be a sign of poor nutrition, advanced gum disease or long-term drug use.
Some body signs are more statistical correlations than causal relationships. Short leg length has been linked to a higher risk for diabetes, atherosclerosis and heart disease, which could all be due to poor nutrition in utero or early childhood. Several studies have found that the shorter a man's index finger in relation to his ring finger, the more aggressive he's likely to be. One possible explanation is exposure to testosterone in the womb, but so far, that remains more a curiosity than a clue.
Of course, being vigilant about your body signs can show you just how imperfect you are. 'You wouldn't believe what else I came down with writing the book,' Ms. Liebmann-Smith says. 'I developed an eye tic. I had a ganglion cyst and giant floaters. And my co-author complained that I was belching a lot. It turned out I was lactose intolerant. I also had GERD [gastroesophageal reflux disease], so I was hoarse all the time. Who would have thought that something to do with your stomach would cause hoarseness?'
史密斯说：“我身上所有的典型症状都有，却被我忽视了。”身为一名医学作家，她决定撰写一本针对非专业人士的书籍，内容是预示重大疾病的身体信号。她与杰奎琳•纳尔迪•伊甘（Jacqueline Nardi Egan）──她是一位乳腺癌幸存者──合作撰写的《从头到脚的健康信号》（“Body Signs”）于2007年出版，已在26个国家发行。
从头到脚仔细检查病人的身体，寻找此类迹象，是护士培训的一项重要部分。家庭护理执业医师苏珊•丹曼（Susan Denman）在杜克大学护理学院（Duke University School of Nursing）教授身体评估课程，她说：“这是病患护理的基础。”了解这些信号和症状的含义在医生的培训中占有很大的比重，医生还需在其整个职业生涯的临床实践中不断完善这个本领。
不过很多医生护士都说，病人自己也必须对自身一些新的或者不同寻常的症状予以重视。爱达荷州博伊西（Boise）的执业医生、美国家庭医生学会（American Academy of Family Physicians）主席泰德•埃珀利（Ted Epperly）说：“病人越上心越好。”
在临床医生看来，过高的体重指数（body-mass index）通常都是一个危险的信号。不过原因不明的体重突降也许更值得担 。布鲁尔医生说：“在这个年纪，一般人体重都是增加，假使有人没有经过任何努力就减肥了，那有可能是患了忧郁症、胃肠疾病或者吸收不良综合症。糖尿病也可能会导致体重下降。”
口腔是另外一个了解身体综合健康状况的窗口。正因为此，纽约大学牙科学院（New York University's College of Dentistry）与护理学院携手在学校的免费牙科诊所为病人检查其他的健康问题。牙科诊所60%以上的病人符合高血压的标准，30%患有糖尿病或前驱糖尿病。护理学院临床实践事务主任爱德威治•托马斯（Edwidge Thomas）说：“他们是因为牙疼才来看病的，而糖尿病和高血压的症状通常都不是那么明显。”